simplify square root of 27r^5

Your problem:

√27r^5

Try to break this down as far as you can to simplify.

√(9 * 3)(r^4 * r)

The square root of 9 is 3. The square root of r^4 is r^2.

Therefore, you end up with this:

3r^2√3r ---> 3r is left under the square root sign.

I hope this will help.